Tulane National Primate Research Center (TNPRC) has one of the largest rhesus monkey breeding colonies in the US. This resource has provided animals for NIH funded research projects for several decades and is a critical component of the Center's successful research program. Because over half of all research projects at TNPRC are initiated by outside investigators, this resource is also essential to the success of many NIH- funded investigators throughout the country. Several years ago the TNPRC established the goal of converting its rhesus monkey breeding colony completely to specific pathogen free (SPF) status. A major step toward that goal was the award of this U42 grant in 2001 to provide funds to establish an SPF Indian- origin rhesus monkey colony at the TNPRC to provide monkeys for NIH-funded AIDS research. The objective of this application is to request funds for continued support and maintenance of this SPF rhesus monkey breeding colony at the TNPRC. The Specific Aims are: 1) to provide husbandry and veterinary care for the SPF breeding colony established in the existing U42 grant. Per diem is requested for 1000 animals per year, 2) to assure the SPF status of the colony through continued viral and genetic testing of existing breeding colony animals and all offspring. All animals in the colony will be tested twice per year for type D simian retrovirus (SRV), and simian T lymphotropic virus (STLV1), B virus, and simian immunodeficiency virus (SIV). Additionally, each year ail yearlings will be sampled for genetic analysis and MHC typing, 3) maintain an average population of 1000 animals, produce 300 live births, and assign 150 animals to NIH funded AIDS projects. This colony is essential to continue to provide high quality, well characterized animals for our expanding AIDS research program that supports hundreds of NIH funded investigators at the TNPRC and throughout the US, 4) program income will be used to offset costs for maintenance items that are not covered by per diem. The colony has reached a mature status with ideal demographics to produce 150 animals available for assignment each year.